It is very easy to spot them, especially on platforms like Twitter where they spread obvious, blatant lies. No one is immune, especially with disinformation campaigns being waged by domestic parties, corporate interests, PR firms.
It has always been a reality that the internet attracts misinformation and conspiracy, even more so in the past than now. And yet, we continue to evolve from a technology that doesn't allow for us to distinguish fantasy from reality.
Or we shouldn't be.
We shouldn't be threatened by foreign posters claiming this or that. If legitimate problems are brought up they should be acknowledged in a free society. If lies are brought up they should be ignored or addressed. But this OMG Russian Posters Everywherez is disturbing. It signals fear and weakness. It's more disturbing than the actual existence of Russian posters. Let them post. Listen to what they say if you care. It should not be a real threat if we are right. If we are not right we should get right.
However if what is being said is true maybe the bigger problem is not _who_ is saying what but rather that this truth exists to be said and maybe we should do something about that rather than ascribing motives which may or may not be accurate.